MAS Defense is a AR-15, AR-10 and Glock parts store. BLK because the pressure levels vary a good deal with different loads. Whats more, the upper receiver and barrel can be swapped out at a ton of. Nav Menu 8. Waiting. Home > PRODUCTS > UPPERS > AR-15 Upper Assemblies · Like Radical Firearms on Facebook · FollowRadical Firearms on Twitter.

These will not have customizations available, they will be ae in the configuration. You can buy a complete, pre-assembled AR-15 upper or ar 15 complete upper deals stripped upper ypper.

High Performance custom Ar-15s that are built to withstand the toughest challenges. I noticed that the fit was.